Human immunodeficiency virus/acquired immunodeficiency syndrome is an important public health problem throughout the world, with sex being the predominant mode of transmission of HIV. Despite the fact that awareness of HIV and AIDS transmission is pervasive, risky sexual behavior has been increasing in many parts of the world in recent years, with a concomitant rise in new cases of HIV and other sexually transmitted diseases (STDs) (Centers for Disease Control and Prevention, 2003; Desquilbet et al., 2002; Rosenberg and Biggar, 1998; Wolitski et al., 2001). The World Heath Organization (WHO) and Joint United Nations Programme on HIV/AIDS (UNAIDS) (2000) has recommended that surveillance of the HIV/AIDS epidemic should focus on populations most at risk of becoming newly infected with HIV—populations with high levels of risk behavior, including young people, men who have sex with men, and racial and ethnic minority heterosexual men and women.

Studies have shown that populations living with HIV and/or at risk for acquiring HIV are at elevated risk for psychiatric conditions (Bing et al., 2001; Lipsitz et al., 1994; Lyketsos et al., 1994; Williams et al., 1991). Thus, it is important to investigate the association between high-risk sexual behavior and psychiatric symptoms as part of the public health response to the HIV pandemic. While the findings have been mixed, a number of studies have found an association between elevated sexual risk behavior and the prevalence of psychiatric disorders (Axis I and Axis II) and psychiatric symptomatology. In this article, we review some of the major findings in this field, discuss hypothesized causal pathways for the association between psychopathology and sexual risk behavior, and address the implications for health care settings.

Substance Use and Abuse

Psychoactive substance use and abuse have consistently been found to be associated with sexual risk behavior and the acquisition or transmission of STDs/HIV among men and women (Harvey and Spigner, 1995; Katz et al., 2000; Stall and Purcell, 2000; Wingood and DiClemente, 1998). Most of these studies assessed frequency and amount of use of alcohol and illicit substances and did not assess the presence or absence of substance use disorders. Substances that were most often cited as being related to sexual risk behavior include alcohol, marijuana, crack, cocaine, methamphetamines and other recreational drugs. Among adolescents, Boyer et al. (2000) found that alcohol and marijuana use were substantially more common among sexually experienced adolescents than the national average. It has been shown that cigarette, alcohol and marijuana use are significant predictors of risky sexual behavior (Cooper, 2002; Harvey and Spigner, 1995; Malow et al., 2001).

Unfortunately, systematic comparisons have not yet been conducted regarding the associations of different types of mood disorders with sexual risk behaviors. According to the DSM-IV, one of the main features of a manic episode is often hypersexuality. However, unipolar depression is much more pervasive than bipolar disorder. Although many people with relatively severe unipolar disorders do have reduced libido, there are many other people with depression who have fluctuating levels of libido that may often be high enough to lead to risky sexual behavior. Furthermore, unipolar depression increases risk for suicidal and self-destructive behavior. People who are self-destructive are perhaps less likely to inhibit their sexual impulses, because if they do not care about life itself, they may reason that there is no reason to care whether they acquire an STD.

In a large cross-sectional birth cohort study, young adults diagnosed with substance dependence, schizophrenia spectrum, depressive, manic and antisocial disorders were more likely to engage in risky sexual intercourse, contract sexually transmitted diseases and have sexual intercourse at an early age (younger than 16) (Ramrakha et al., 2000). Furthermore, the likelihood of risky behavior was increased by psychiatric comorbidity. This study was one of the first to establish strong links between a wide range of psychiatric disorders and sexual risk behavior. More specifically, they found that compared to people without psychiatric disorders, those with anxiety disorders were more likely to report STDs; those with depressive, substance dependence and antisocial disorders were more likely to engage in sexual risk behaviors, report STDs and were younger at first sexual intercourse; those with mania were more likely to have engaged in risky sexual behavior and to report STDs; and those with symptoms in the schizophrenia spectrum were more likely to engage in sexual risk, report STDs and were younger at first sexual intercourse. The strongest association of risky sexual behavior was with disorders characterized by disinhibition or a pattern of impulsive behavior and comorbid psychiatric conditions. In particular, depression, substance dependence and antisocial disorders showed stronger associations with risky behavior compared with any single psychiatric disorder.

While many studies have found that sexual risk taking was associated with the presence of negative mood states and Axis I disorders, there have been studies that failed to find such an association. Dilley et al. (1998) found no association between depression scores and sexual risk among sexually active gay men. Dolezal et al. (2000) found positive self-esteem to be associated with greater sexual risk behavior and Robins et al. (1994) found an association between sexual risk and lower levels of psychological distress. Rubb et al. (1993) also found depressed ideation was associated with a reduced likelihood to engage in sexual risk behavior. Rogers et al. (2003) found two patterns of association between depressive disorders and sex behavior. Major depression was associated with reduced sexual activity, while dysthymic disorder was associated with an increased likelihood of unprotected sex.